1. Field of the Invention
The present invention relates to back rests and more particularly, to a lightweight, portable back rest of foldable construction which can be readily attached to a stadium bleacher seat or the like.
2. Discussion of the Prior Art
Many arenas or stadiums designed for spectator sports such as football, track, soccer, road racing, and the like, are provided with bleacher or plank-type seating. Such seating does not have back supports and is extremely uncomfortable, particularly for sports of long duration such as football and road racing. Consequently, many attempts have been made in the past to design portable back rests which may be carried by the spectator to the stadium and clamped or otherwise affixed to the bleacher seats and the prior art is replete with back rests of various configurations.
Perhaps the most common type of prior art back rest comprises a foldable metal framework upon which is mounted a back support member and a seat cushion. Gripping members in the form of adjustable clamps or gripping prongs are usually provided to affix the seat back to the forward edges of the bleacher seat. Generally, prior art back rests of this design were heavy, bulky, awkward to transport, and frequently difficult to affix securely and safely to the bleacher seat. Moreover, because of their rigid construction, they were often quite uncomfortable, having planar, upright backs which would not conform to or adequately support the back of the user. Also, because of the rather complicated construction of this class of back rest, they were often difficult and expensive to manufacture.
Exemplary of prior art seat backs of the aforementioned character are those described in the following U.S. Letters Patents:
______________________________________ 2,092,666 - Dietrich 466,873 - Hardendorf 2,466,361 - Bjornskaas 2,425,884 - Janssen ______________________________________
Other types of seat backs of rigid or semirigid construction known to applicant include those described in the following U.S. Letters Patents:
______________________________________ 3,359,036 Druth, et al. 1,780,570 Stephens 2,710,646 Kirby ______________________________________
A significantly improved seat back construction, of which the present invention is an improvement, is described in application Ser. No. 569,203, filed by James E. Pierce. The Pierce seat back is constructed of a single sheet of flexible material and may be flexed from its flat transport and storage condition to its operative condition for combination with a bleacher seat.
As will become apparent from the discussion which follows, the seat back of the present invention is superior in numerous respects to each of the various prior art structures previously identified. It is lightweight, extremely compact in its transport condition, and can readily be affixed to a bleacher seat without the use of tools and without the necessity for manipulation of screws, clamps, or other mechanical fasteners. Because it is formed of a unitary piece of flexible material, it is quite inexpensive to manufacture and is extremely durable. Additionally, because of its unique design, the seat back of the present invention is very comfortable in use and is highly safe and stable in its operative configuration. The safety and comfort of the seat back is enhanced by the unique locking means of the unit which permits it to tilt rearwardly so as to provide greater comfort and, at the same time, securely lock against bleacher seats of varying thickness.